The primary protocol to be implemented by the X.25 service is the X.25 CCITT standard, 1988 version. Other related protocols are X.75, X.32, and the "triple X" PAD (Packet Assembler-Dissembler) (X.3, X.28, X.29).
Until now, packet switches have been built on trunking and routing systems that use simple circuit switching or point-to-point data communications technologies. This provided no flexibility and control of the individual virtual circuits when parts of the backbone network became congested.
X.25 is an interface specification for statistically multiplexing several independent data streams onto common facilities. It uses a link layer based on HDLC frames, using LAPB between the DTE and the DCE.
An object of this invention is to provide an improved network supporting X-series packet and call protocol.